Hmmm jenkins is case sensitive and is configured to use lower case release and debug. Build.cmd use Release and Debug.

build.cmd

@@ -32,7 +32,7 @@ set BUILD_CORECLR=0
 set BUILD_PORTABLE=0
 set BUILD_VS=0
 set BUILD_FSHARP_DATA_TYPEPROVIDERS=0
-set BUILD_CONFIG=Release
+set BUILD_CONFIG=release
 set BUILD_CONFIG_LOWERCASE=release
 
 set TEST_COMPILERUNIT=0
@@ -148,7 +148,7 @@ if /i '%ARG%' == 'coreclr' (
 )
 
 if /i '%ARG%' == 'debug' (
-    set BUILD_CONFIG=Debug
+    set BUILD_CONFIG=debug
     set BUILD_CONFIG_LOWERCASE=debug
 )
 
@@ -257,13 +257,13 @@ if not exist %_dotnetexe% (
   @if ERRORLEVEL 1 echo Error: dotnet publish failed  && goto :failure
 
   rem rename fsc and coreconsole to allow fsc.exe to to start compiler
-  pushd .\lkg\bin\Debug\dnxcore50\win7-x64\publish
+  pushd .\lkg\bin\debug\dnxcore50\win7-x64\publish
   ren fsc.exe fsc.dll
   copy corehost.exe fsc.exe
   popd
 
   rem rename fsi and coreconsole to allow fsi.exe to to start interative
-  pushd .\lkg\bin\Debug\dnxcore50\win7-x64\publish 
+  pushd .\lkg\bin\debug\dnxcore50\win7-x64\publish 
   ren fsi.exe fsi.dll
   copy corehost.exe fsi.exe
   popd

netci.groovy

@@ -15,7 +15,7 @@ def static getBuildJobName(def configuration, def os) {
 }
 
 [true, false].each { isPullRequest ->
-    ['debug', 'release'].each { configuration ->
+    ['Debug', 'Release'].each { configuration ->
         osList.each { os ->
 
             def lowerConfiguration = configuration.toLowerCase()
@@ -51,8 +51,8 @@ def static getBuildJobName(def configuration, def os) {
 
             Utilities.setMachineAffinity(newJob, os, 'latest-or-auto')
             Utilities.standardJobSetup(newJob, project, isPullRequest, "*/${branch}")
-            //Utilities.addXUnitDotNETResults(newJob, 'tests/TestResults/**/*_Xml.xml', skipIfNoTestFiles)
-            //Utilities.addArchival(newJob, "${lowerConfiguration}/**")
+            Utilities.addXUnitDotNETResults(newJob, 'tests/TestResults/**/*_Xml.xml', skipIfNoTestFiles)
+            Utilities.addArchival(newJob, "${lowerConfiguration}/**")
 
             if (isPullRequest) {
                 Utilities.addGithubPRTriggerForBranch(newJob, branch, "${os} ${configuration} Build")